1. Field of the Invention
The present invention relates to a cylinder lock device, in more particular, to a cylinder lock device which is difficult to unlock by an unauthorized picking operation.
2. Related Art
As a cylinder lock device used for the doors or the like of the vehicle, a cylinder lock device having a rotor arranged to be rotatable inside a rotor case in a cylindrical shape and formed such that a key insert hole extends in an axial direction, has been known. In the cylinder lock device, a plurality of tumblers are provided in the rotor to be movable in a radial direction, and each tumbler is biased toward an outer radial direction and engaged with a sleeve when a key is inserted into a key insert hole, each tumbler is moved by a groove of the key. When a regular key is inserted. The engagement of each tumbler with the sleeve is released, so that the rotor and the sleeve are separated from each other to be rotatable. By rotating the key, a lever member is rotated together with the rotor to conduct the locking or unlocking operation.
As a cylinder lock device of this type, a free-wheel mechanism has been proposed, which rotates only a rotor and a sleeve wilt respect to a rotor case when a foreign object such as an unauthorized key or a screwdriver is inserted. A cylinder lock device disclosed by JP-A-8-004378 is provided with a shift factor movable in a radial direction in the rotor, in which this shift factor is engaged with a concave portion formed on an outer peripheral surface of the sleeve biasing to the inner radial direction. Furthermore, it is configured that the sleeve is rotatable with respect to the rotor case by a movement of the shift factor engaged with the sleeve in an outer radial direction when the rotor is rotated by a key other than a regular key.
However, in the cylinder lock device disclosed by JP-A-8-004378, since the tumbler contacts with the rotor when operating each of the tumblers while rotating the rotor, it is possible to find a true position for each tumbler, namely, a position to allow the unlocking by moving the tumbler up and down in this contact state, thus, there is a problem in that it is possible to carry out a so-called unauthorized picking action.